<!--
    /**
     * 树形下拉选择组件，下拉框展示树形结构，提供选择某节点功能，方便其他模块调用
     * @author sxy https://bysjb.cn
     * @date 2020-12-02
     */
-->
<template>
  <div>
    <div v-show="isShowSelect" class="mask" @click="isShowSelect = !isShowSelect" />
    <el-popover
      v-model="isShowSelect"
      placement="bottom-start"
      :width="width"
      trigger="manual"
      style="padding: 12px 0;"
      @hide="popoverHide"
    >
      <el-tree
        ref="tree"
        class="common-tree"
        :style="style"
        :data="data"
        :props="defaultProps"
        :show-checkbox="multiple"
        :node-key="nodeKey"
        :check-strictly="checkStrictly"
        default-expand-all
        :expand-on-click-node="false"
        :check-on-click-node="multiple"
        :highlight-current="true"
        @node-click="handleNodeClick"
        @check-change="handleCheckChange"
      />
      <el-select
        slot="reference"
        ref="select"
        v-model="selectedData"
        :style="selectStyle"
        :size="size"
        :multiple="multiple"
        :clearable="clearable"
        :collapse-tags="collapseTags"
        class="tree-select"
        @click.native="isShowSelect = !isShowSelect"
        @remove-tag="removeSelectedNodes"
        @clear="removeSelectedNode"
        @change="changeSelectedNodes"
      >
        <el-option v-for="item in options" :key="item.value" :label="aa(item)" :value="item.value" />
      </el-select>
    </el-popover>
  </div>
</template>

<script>
  export default {
    props: {
      // 树结构数据
      data: {
        type: Array,
        default() {
          return []
        }
      },
      defaultProps: {
        type: Object,
        default() {
          return {
            children: 'children',
            label: 'name'
          }
        }
      },
      // 配置是否可多选
      multiple: {
        type: Boolean,
        default() {
          return false
        }
      },
      // 配置是否可清空选择
      clearable: {
        type: Boolean,
        default() {
          return false
        }
      },
      // 配置多选时是否将选中值按文字的形式展示
      collapseTags: {
        type: Boolean,
        default() {
          return false
        }
      },
      nodeKey: {
        type: String,
        default() {
          return 'id'
        }
      },
      // 显示复选框情况下，是否严格遵循父子不互相关联
      checkStrictly: {
        type: Boolean,
        default() {
          return false
        }
      },
      // 默认选中的节点key数组
      checkedKeys: {
        type: Array,
        default() {
          return []
        }
      },
      size: {
        type: String,
        default() {
          return 'medium'
        }
      },
      width: {
        type: Number,
        default() {
          return 250
        }
      },
      height: {
        type: Number,
        default() {
          return 300
        }
      }
    },
    data() {
      return {
        isShowSelect: false, // 是否显示树状选择器
        options: [],
        selectedData: [], // 选中的节点
        style: 'width:' + (this.width - 24) + 'px;' + 'height:' + this.height + 'px;',
        selectStyle: 'width:' + (this.width + 24) + 'px;',
        checkedIds: [],
        checkedData: [],
        selectedData2:'',
        selectNode:{}
      }
    },
    watch: {
      isShowSelect(val) {
        // 隐藏select自带的下拉框
        this.$refs.select.blur()
      },
      checkedKeys(val) {
        if (!val) return
        this.checkedKeys = val
        this.initCheckedData()
      }
    },
    computed: {
      aa(){
        return  (a)=> {
          if(this.multiple){
            return a.label
          }else {
            return  this.selectedData2.substring(0,this.selectedData2.length-1)
          }
        }
      }
    },
    mounted() {
      this.initCheckedData()
    },
    methods: {
      bb(){return 'wee'},
      // 递归函数
      spliceNode(node) {
        var parent = node.parent;
        if(!parent){
          return ;
        }
        this.selectedData2= node.label+'/'+this.selectedData2
        this.spliceNode(parent)
      },
      // 单选时点击tree节点，设置select选项
      setSelectOption(node) {
        this.selectedData2=''
        const tmpMap = {}
        tmpMap.value = node.key
        tmpMap.label = node.label
        this.options = []
        this.options.push(tmpMap)
        this.selectedData = node.key
        this.spliceNode(node)
      },
      // 单选，选中传进来的节点
      checkSelectedNode(checkedKeys) {
        var item = checkedKeys[0]
        this.$refs.tree.setCurrentKey(item)
        var node = this.$refs.tree.getNode(item)
        this.selectNode=node
        this.setSelectOption(node)
      },
      // 多选，勾选上传进来的节点
      checkSelectedNodes(checkedKeys) {
        // this.$refs.tree.setCheckedKeys(checkedKeys)

        // 优化select回显显示 有个延迟的效果
        const that = this
        setTimeout(function() {
          that.$refs.tree.setCheckedKeys(checkedKeys)
        }, 10)
        // console.log('checkSelectedNodes', checkedKeys, this.selectedData)
      },
      // 单选，清空选中
      clearSelectedNode() {
        this.selectedData = []
        this.$refs.tree.setCurrentKey(null)
      },
      // 多选，清空所有勾选
      clearSelectedNodes() {
        var checkedKeys = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
        for (let i = 0; i < checkedKeys.length; i++) {
          this.$refs.tree.setChecked(checkedKeys[i], false)
        }
      },
      initCheckedData() {
        if (this.multiple) {
          // 多选
          // console.log(this.checkedKeys.length)
          if (this.checkedKeys.length > 0) {
            this.checkSelectedNodes(this.checkedKeys)
          } else {
            this.clearSelectedNodes()
          }
        } else {
          // 单选
          if (this.checkedKeys.length > 0) {
            this.checkSelectedNode(this.checkedKeys)
          } else {
            this.clearSelectedNode()
          }
        }
      },
      popoverHide() {
        if (this.multiple) {
          this.checkedIds = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
          this.checkedData = this.$refs.tree.getCheckedNodes() // 所有被选中的节点所组成的数组数据
        } else {
          this.checkedIds = this.$refs.tree.getCurrentKey()
          this.checkedData = this.$refs.tree.getCurrentNode()
        }
        this.$emit('popoverHide', this.checkedIds, this.checkedData)
      },
      // 单选，节点被点击时的回调,返回被点击的节点数据
      handleNodeClick(data, node) {
        if (!this.multiple) {
          this.setSelectOption(node)
          this.isShowSelect = !this.isShowSelect
          this.$emit('change', this.selectedData)
        }
      },
      // 多选，节点勾选状态发生变化时的回调
      handleCheckChange() {
        var checkedKeys = this.$refs.tree.getCheckedKeys() // 所有被选中的节点的 key 所组成的数组数据
        // console.log('handleCheckChange', checkedKeys)

        this.options = checkedKeys.map((item) => {
          var node = this.$refs.tree.getNode(item) // 所有被选中的节点对应的node
          const tmpMap = {}
          tmpMap.value = node.key
          tmpMap.label = node.label
          return tmpMap
        })
        this.selectedData = this.options.map((item) => {
          return item.value
        })
        this.$emit('change', this.selectedData)
      },
      // 多选,删除任一select选项的回调
      removeSelectedNodes(val) {
        this.$refs.tree.setChecked(val, false)
        var node = this.$refs.tree.getNode(val)
        if (!this.checkStrictly && node.childNodes.length > 0) {
          this.treeToList(node).map(item => {
            if (item.childNodes.length <= 0) {
              this.$refs.tree.setChecked(item, false)
            }
          })
          this.handleCheckChange()
        }
        this.$emit('change', this.selectedData)
      },
      treeToList(tree) {
        var queen = []
        var out = []
        queen = queen.concat(tree)
        while (queen.length) {
          var first = queen.shift()
          if (first.childNodes) {
            queen = queen.concat(first.childNodes)
          }
          out.push(first)
        }
        return out
      },
      // 单选,清空select输入框的回调
      removeSelectedNode() {
        this.clearSelectedNode()
        this.$emit('change', this.selectedData)
      },
      // 选中的select选项改变的回调
      changeSelectedNodes(selectedData) {
        // 多选,清空select输入框时，清除树勾选
        if (this.multiple && selectedData.length <= 0) {
          this.clearSelectedNodes()
        }
        this.$emit('change', this.selectedData)
      }
    }

  }
</script>

<style scoped>
  .mask {
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0;
    left: 0;
    opacity: 0;
    z-index: 11;
  }

  .common-tree {
    overflow: auto;
  }

  .tree-select {
    z-index: 111;
  }
</style>
